All the suffering we experience in this life, such as sickness, poverty, conflict, accidents, and harm from humans and non-humans, is the result of our own past negative karma.
Geshe Kelsang Gyatso, The New Meditation Handbook

Geshe Kelsang Gyatso has written nineteen books on Buddhism. Their purpose is to reveal the teachings and practices of Kadampa Buddhism to the modern day reader in a clear and accessible way.
This remarkable series of authoritative books represents the most complete and integrated presentation of the Buddhist path to enlightenment available in any western language. Originally written in English they are currently being translated into many of the world's major languages.
Ranging from highly accessible books
for beginners to detailed and lucid expositions of the profundities
of Buddhist philosophy and Tantric practice, each book is
a practical manual for meditation and a guide on how to follow
the Buddhist way of life. 
Geshe Kelsang has also translated all the meditation practices or sadhanas of Kadampa Buddhism from their original Tibetan and encouraged the chanting of these prayers in English and other languages.
The Tharpa website has an extensive range of Buddhist books, audiobooks, and artwork.